The present invention relates to a power supply system which is made up of a plurality of batteries connected together in series and which is installed in a hybrid vehicle which can run by powers of both an internal combustion engine and an electric motor or an electric vehicle.
A power supply system 100 such as shown in FIG. 7 or 8, for example, is installed in a hybrid vehicle which can run by powers of both an internal combustion engine and an electric motor or an electric vehicle. The power supply system 100 shown in FIG. 7 or 8 includes a plurality of batteries 101 which are arranged so that different electrodes 105, 106 lie adjacent to each other, busbars 109 which each connect together the batteries 101 which lie adjacent to each other, a busbar module 103 in which a plurality of busbar accommodating spaces 102 are provided which each accommodate a busbar 109, and terminals 104 which connect to a voltage detection means (not shown) for measuring a potential difference between the positive electrodes 105 and the negative electrodes 106 which are connected together by the busbars 109.
In each battery 101, the positive electrode 105 is provided at one end and the negative electrode 106 is provided at the other end. In the batteries 101 which lie adjacent to each other, the positive pole 105 and the negative pole 106 lie adjacent to each other. Namely, the plurality of batteries 101 are aligned in such a state that the positive electrodes 105 and the negative electrodes 106 are located in opposite positions alternately.
The busbars 109 connect together the batteries 101 which lie adjacent each other and the positive electrodes 105 and the negative electrodes 106 which lie adjacent to each other so as to connect the batteries 101 in series.
The plurality of busbar accommodating spaces 102 are provided in the busbar module 103. The busbar module 103 is attached to end faces of the batteries 101 aligned. The busbar accommodating spaces 102 each accommodate the busbar 109 and the terminal 104 which connect to the voltage detection means.
The busbar accommodating space 102 is made up of a plurality of bulkheads 102a. The bulkheads 102 are each formed into a rectangular shape when viewed from the top. The plurality of bulkheads 102a are provided to be erected so as to encompass the busbar 109 and the terminal 104.
The bulkhead 102a includes a busbar fitting portion 107. The busbar fitting portion 107 includes a busbar locking portion 107A and a terminal locking portion 107B.
The busbar locking portion 107A is provided so as to project towards an inside of the busbar accommodating space 102. The busbar locking portion 107A presses the busbar 109 in a direction in which the battery 101 is disposed to thereby lock the busbar 109 in the busbar accommodating space 102.
The terminal locking portion 107B is provided so as to be spaced apart from the busbar locking portion 107A. The terminal locking portion 107B includes a slit 108A which is provided so as to penetrate through the bulkhead 102a and a frame portion 108B which is formed on an external surface of the bulkhead 102a. 
The slit 108A is formed parallel to the end face of each of the batteries 101 which are aligned with one another. The slit 108A is formed into a straight-line shape when viewed from the top, so that an entering portion 104c of the terminal 104 can enter it.
The frame portion 108B is formed so as to project from the external surface of the bulkhead 102a. The frame portion 108B is formed into a substantially U-shape so as to connect both ends of the slit 108A.
The terminal 104 includes a main body portion 104a which is formed into a substantially rectangular shape and a connecting portion 104b. The terminal 104 is formed into a plate-like shape. The terminal 104 connects to the voltage detection means to measure potentials of the electrodes 105, 106 of the corresponding battery 101.
The entering portion 104c is provided on the main body portion 104a. The entering portion 104c is provided so as to extend outwardly of the busbar accommodating space 102 from the main body portion 104a. The entering portion 104c enters the slit 108A.
In the power supply system 100 that is configured as has been described heretofore, when the terminal 104 rotates about the electrode 105 or 106, in the terminal locking portion 107B, an outer edge of the entering portion 104c that has entered the slit 108A is brought into abutment with an inner edge of the frame portion 108B to thereby prevent the terminal 104 from rotating about the electrode 105 or 106 to which the terminal 104 is attached.    [Patent Document 1] Japanese Patent Publication Number 2003-45409
As described above, the related power supply system 100 has the construction in which the busbar locking portion 107A which mounts the busbar 109 in the busbar accommodating space 102 is independent from the terminal locking portion 107B which prevents the terminal 104 from rotating about the electrode 105 or 106. Because of this, there has been a tendency that the busbar fitting portion 107 is formed large. Further, there has been a tendency that the busbar fitting portion has a complex configuration. In addition, there has been a problem that the amount of a resin material used for the busbar fitting portion 107 is increased.